1. Field of the Invention
The present invention relates to a single-headed-piston-type swash-plate compressor used in, for example, an air-conditioning system incorporated in a vehicle such as an automobile, and more particularly, to a single-headed piston type swash-plate compressor having a damping system for suppressing pulsations in the discharge pressure of a compressed refrigerant gas.
2. Description of the Related Art
Generally, a single-headed-piston-type swash-plate compressor comprises: a cylinder block having a plurality of cylinder bores radially formed therein and arranged with respect to the central axis thereof; a plurality of pistons slidably received in the cylinder bores, respectively; a front housing securely fixed to a front end wall of the cylinder block to form a crank chamber therebetween; a drive shaft axially extended through the crank chamber such that the ends thereof are rotatably supported by the front housing and the cylinder block, respectively; a conversion mechanism provided on the drive shaft within the crank chamber for converting a rotating movement of the drive shaft into a reciprocating movement of the pistons; a rear housing or cylinder head housing securely fixed to a rear end wall of the cylinder block to form a suction chamber and a discharge chamber therebetween; and a valve plate assembly provided between the cylinder block and the cylinder head housing.
The valve plate assembly in particular comprises: a disc-like member having several sets of a suction port and a discharge port opened to the suction chamber and the discharge chamber, respectively, each set being able to communicate with the corresponding one of the cylinder bores in the cylinder block; an inner valve sheet attached to the inner side surface of the disc-like member and having suction reed valve elements formed integrally therein, each of which is arranged so as to open and close the corresponding suction port in the disc-like member; and an outer valve sheet attached to the outer side surface of the disc-like member and having discharge reed valve elements formed integrally therein, each of which is arranged so as to open and close the corresponding discharge port in the disc-like member.
When the compressor is incorporated in an air-conditioning system for a vehicle such as an automobile, the drive shaft is rotationally driven by the prime mover or engine of the automobile, and the suction chamber and the discharge chamber are in communication with an evaporator and a condenser of the air-conditioning system through an inlet port and an outlet port formed in the cylinder head housing, to allow a refrigerant gas to circulate in the air-conditioning system. The rotational movement of the drive shaft causes the pistons to be reciprocated in the cylinder bores due to the conversion mechanism provided on the drive shaft within the crank chamber. When each piston is reciprocated in the corresponding cylinder bore, and thus a suction stroke and a compression stroke are repeatedly executed therein, a suction stroke is executed in one of the aligned cylinder bores. During the suction stroke, the suction reed valve element is opened and the discharge reed valve element is closed, whereby the refrigerant gas is delivered from the suction chamber to the cylinder bore through the suction port. During the compression stroke, the suction reed valve element concerned is closed and the discharge reed valve element concerned is opened, whereby the delivered refrigerant gas is compressed and discharged from the cylinder bore into the discharge chamber, through the discharge reed valve element.
The operation of the compressor as described above, produces pulsations in the discharge pressure of the compressed refrigerant gas, and the pulsations cause noise and vibration. To prevent the noise and vibration, the compressor can be provided with a damping chamber for suppressing the pulsations in discharge pressure of a compressed refrigerant gas, as disclosed in, for example, Unexamined Japanese Utility Model Publication No. 50(1975)-44313. In particular, the damping chamber is incorporated in the cylinder head housing such that the damping chamber is in communication with the discharge chamber through small passages provided therebetween, and has an outlet port formed in a wall portion defining the damping chamber. Using this arrangement, the pulsations can be suppressed by passing the compressed and discharged refrigerant gas from the discharge chamber into the damping chamber through the small passages. Nevertheless, the incorporation of the damping chamber in the cylinder head housing results in an increase in the axial length thereof. An increase in the axial length of the compressor should be avoided because there is a strong demand for making the axial length of the compressor as small as possible, especially in the automobile field.
In a double-headed piston type swash-plate compressor, the damping chamber is frequently provided on a side wall of the compressor so as to avoid an increase in the axial length thereof, and the damping chamber is in communication with the discharge chamber through a passage formed in the cylinder block and arranged between the adjacent cylinder bores. However, his concept cannot be applied to the single-headed-piston-type swash-plate compressor because the thickness of the portion in the cylinder block between the adjacent cylinder bores is relatively thin in comparison with the corresponding portion of the cylinder block of the double-headed-piston-type swash-plate compressor.